I just though I would let you know that the notches in your board are not holes or cutouts as far as Fritzing is concerned. You could draw your outline using any method you want as long as it is a complete outline without any breaks. It is just the actual holes that need to be a difference operation and the difference needs to be done last. If you read my 3rd tip Inkscape Tips and Tricks it explains how to fix a board that has been made incorrectly without having to start over. Like if you decide you want to make the bottom right tab longer you could move the vertices and then follow my 3rd tip and still get a working board. Otherwise you would have to start with a larger board and do all your differences again plus another to make the tab above the bottom right shorter since the goal of my hypothetical change is making the bottom right tab longer. Be sure to read my entire tips and tricks thread it has a lot of useful information.